Mineral oil composition



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3,012,967 MINERAL 01L COMPOSITION Samuel J. Leonardi, Pitman, and Edward A. Oberright,

Woodbury, N.J., assignors to Socony Mobil Oil Company, Inc., a corporation of New York No Drawing. Filed July 26, 1957, Ser. No. 674,279 4 Claims. (Cl. 252-482) This invention has to do with the stabilization of petroleum fractions, particularly .of lubricating oils. More specifically, it relates to petroleum fractions having incorporated therein certain combinations of additives in ject to attack by the acidic oxidation products formed in the oil in use. Furthermore, these oxidation products produce formations of varnish and sludge on the engine surfaces which lower the operating efiiciency of the engine. Also, due to oxidation effects, the viscosity of the oil is changed in use so that proper lubrication of the engine parts is not obtained. Inthe case of turbine oils, the problem of oxidation is increased since the oil normally becomes contaminated with water. 1

It is an object of this invention, therefore, to provide a class of addition agents for petroleum oil fractions which are capable of substantially inhibiting the oxidative deterioration of such fractions. A further object is to provide petroleum compositions, such as lubricating oils, which are highly stabilized against oxidation under the conditions of use. 1 1

It is an object of this invention to stabilize mineral lubricating oils against the deleterious effects of oxidation.

It is a related object to provide lubricating oil compositions containing certain advantageous combinations of additives, hereinafter described.

Other and further objects will become apparent from the following description of the invention.

It has been found that the foregoing objects can be realized by incorporating into a lubricating oil fraction, a small amount of each of: (1) an aromatic hydroperoxide having a hydroperoxy group attached to an alpha carbon atom of an aryl nucleus thereof, and (2) an acid Whose dissociation constant in water is at least about 1.0 1

It is to be understood that no claim is made herein to an oil containing a hydroperoxide (1) in the absence of an acid (2), since such are shown by Watkins in U.S. Patent No. 2,470,276. Similarly, no claim is made to an oil containing an acid (2) in the absence of a hydroperoxide (1), for such are shown by Bulkley et al. in

US. Patent No. 2,248,848. In neither of these patents,

nor in any other prior art known to us, is there a showing of an oil containing a hydroperoxide (1) and an acid The latter oils are greatly superior to'oils containing only one of the said two additives. I

The aromatic hydroperoxides 1) of this invention are represented by the following general formulae:

Patented Dec. 12, 1961 2 and A-d-OOH wherein A is an aryl group, such as benzene, naphthalene and biphenyl, or is an alkaryl group wherein the alkyl (or cycloalkyl) substituent can be such as methyl, ethyl, butyl or cyclohexyl; R and R are any combination of hydrogen, cycloalkyl, alkyl, aryl, alkaryl, cycloalkylaryl or aralkyl; and R is an alkyl group of 2.0r 3 carbon carbon is connected to the aryl atoms whose terminal group A.

"Representative of the hydroperoxides contemplated hereinand designated by general Formula a, are: 9:-

cumyl hydroperoxide; a-p-xylyl hydroperoxide: p-cymene I hydroperoxide; a,a-dimethylbenzyl hydroperoxide; OtQ t dimethyl-p-methylbenzyl hydroperoxide; and'e t-dimeth-L ylp-isopr opylbenzyl hydroperoxide.

Representative of the hydroperoxides contemplated herein and designated by general Formula b, are: tetralin hydroperoxide and hydrindene hydroperoxide.

lin hydroperoxides are preferred herein.

As indicated above, the second additive used in the new compositions isan acid whose dissociation constant in water is at least 1.0 10- It is to be understood that the first dissociation constant of a 'polybasic acid (Ka will have such a value. Typical of such acids are: acetic,

Of these compounds, the a-cumyl, 'a-p-xylyl, and tetramonochloracetic, dichloracetic, trichloracetic, iodic, maleic, oxalic, propionic, phosphoric, phosphorous, pyro phosphoric, picric, sulfuric, sulfurous, benzoic, pyromellitic, mellitic, benzene sulfinic, p-toluene sulfonic, and

hydroxydecanoic. Preferred of such acids are phosphoric.

acid and p-toluene sulfonic acid.

. Typical examples of hydroperoxides contemplated herein are revealed by the following:

' EXAMPLE I H v I W Commercial alpha-cumyl hydroperoxide was purified as follows: The sodium salt of alpha-cumyl hydroperoxide was precipitated when the hydroperoxide was contacted with aqueous sodium hydroxide at temperatures below 77 F. The resulting reaction mixture was con' tacted with benzene andthe sodium salt was filtered off with suction. The sodium salt waswashed with ben-. zene, dried, and suspended with water, The hydroper,

oxide was liberated by adding carbon dioxide to the sodium salt, and was extracted with petroleum ether. The ether was then removed by distillation under vacuum. The residue contained 9.87 percent active oxygen (by iodometric titration) and its refractive index was 1.5253. Theoretical values for alpha-cumyl hydroperoxide are 10.52 percent active oxygen and 1.5242 (n respectively.

EXAMPLE II Alpha p-xylyl hydroperoxide was prepared by the following procedure:

Para-xylene was oxidized by bubbling oxygen therethrough. at temperatures between 60 and 65 "C., until" 3 a peroxide number determination-indicated that one per- 1e ether was removed by evaporation. By twice purifyig the p-xylene reaction product through the sodium alt, the hydroperoxide was concentrated to about 55 perent purity. Peroxide number determinations indicated .4 percent of active oxygen in the purified product; the ieoretical value for active oxygen is 11.6 percent.

Oxidation stabilities of blends of a mineral oil conaining combinations of the hydroperoxides and acids con- :mplated herein, were determined. This was in conrast to corresponding tests on the oil alone, the oil conaining a hydroperoxide but not containing an acid, and 1e oil containing an acid but not containing a hydroeroxide. The test used is an oxidation stability test atterned after that described by Larsen, Thorpe and lrmfield in Industrial and Engineering Chemistry 34, 89-93 (1942). In this test oxygen is dispersed by leans of a sintered glass bubbler through the oil at 300 The degree of deterioration of. the oil is determined ry. measuring-theamount of oxygen that reacts with the ii. The results are reported in hours required for aborption of two liters of oxygen per 100 grams of oil. The longer the time for this absorption to take place, he more stable the oil.

The oil used in the tests was a highly acid-refined oil iaving the following properties:

Results of the oxidation stability tests are given in Fable I following:

Table I Hoursv Required for Absorption of 2 Liters 02/100 gms. Oil Blend 00110., percent by Weight Additive ?hosphoric'Aeld i-Toluene Sulfonic Acid llpha-Oumyl Hydroperoxide tlpha-Gumyl Hydroperoxlde ?hosphorie Acid, klpha-Cumyl Hydroperoxide J-Toluene Sulfonic-Acid \lpha-p-Xylyl Hydroperoxide J-Toluene Sulfonic Acid I percent of product 01 Example 11 containing 55 percent of hydro- Jeroxide.

Data given in Table I reveal that the combination of an acid and a hydroperoxide. is surprisingly superior to the results obtained with only one of the said additives.

The amounts of acid and hydroperoxide to be added to a petroleum oil fraction will vary somewhat with the particular oil fraction and the conditions of use. In. general, the amount of acid will be from 0.001 to about 3.0 percent by weight of the oil, preferably 0.01 to 1.0 percent. Correspondingly,-the amountof hydroperoxide Will generally vary from about 0.1 to about 10 percent by weight of the oil; 1.0 to '8 percent is the preferred range. The additives of this invention may, of course, be added to petroleum fractions along withother additive agents designed to improve various other characteristics of such fractions, for example, pour point depressants, extreme pressure agents, detergents and the like.

Although the invention has been illustrated herein by the use of specific examples of my additive products and in a particular petroleum medium, it is not intended that the scope of this invention be many way limited thereby, but only as shown in the accompanying claims.

We claim:

1. A petroleum lubricating oil subject to oxidative deterioration and containing (1) a minor amount, from about 1.0to -8 percent'byweight of the oil, of a hydroperoxide selected from the group consisting of oc-cumyl hydroperoxide and ix,p-xylyl hydroperoxide and tetralin hydroperoxide, and (2) aminor amount, from about 0.01 to 1.0 percent by weight of the oil, of an' acid selected from the group consisting of phosphoric acid and p-toluene sulfonic acid.

2. A petroleum lubricating oil subject to oxidative deterioration and containing about 7.5 percent by weight.

7 weight of p-toluene sulfonic acid.

References Cited in the file'of this patent UNITED STATES PATENTS 2,119,240 Lyons May 31, 1938 2,248,848 Bulkley July 8, 1941 2,249,340 Wilson et al. July 15, 1941 2,470,276 Watkins May 17 1949 2,773,906 Emerson Dec. 11, 1956 

1. A PETROLEUM LUBRICATING OIL SUBJECT TO OXIDATIVE DETERIORATION AND CONTAINING (1) A MINOR AMOUNT, FROM ABOUT 1.0 TO 8 PERCENT BY WEIGHT OF THE OIL, OF A HYDROPEROXIDE SELECTED FROM THE GROUP CONSISTING OF A-CUMYL HYDROPEROXIDE AND A,P-XYLYL HYDROPEROXIDE AND TETRALIN HYDROPEROXIDE, AND (2) A MINOR AMOUNT, FROM ABOUT 0.1 TO 1.0 PERCENT BY WEIGHT OF THE OIL, OF AN ACID SELECTED FROM THE GROUP CONSISTING OF PHOSPHORIC ACID AND P-TOLUENE SULFONIC ACID. 